Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D4/00—Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/13—Phenols; Phenolates
  • C08K5/134—Phenols containing ester groups
  • C08K5/1345—Carboxylic esters of phenolcarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/34—Heterocyclic compounds having nitrogen in the ring
  • C08K5/3412—Heterocyclic compounds having nitrogen in the ring having one nitrogen atom in the ring
  • C08K5/3432—Six-membered rings
  • C08K5/3435—Piperidines
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/51—Phosphorus bound to oxygen
  • C08K5/53—Phosphorus bound to oxygen bound to oxygen and to carbon only
  • C08K5/5397—Phosphine oxides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K9/00—Use of pretreated ingredients
  • C08K9/04—Ingredients treated with organic substances
  • C08K9/06—Ingredients treated with organic substances with silicon-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
  • C09D175/14—Polyurethanes having carbon-to-carbon unsaturated bonds
  • C09D175/16—Polyurethanes having carbon-to-carbon unsaturated bonds having terminal carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/48—Stabilisers against degradation by oxygen, light or heat
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/60—Additives non-macromolecular
  • C09D7/61—Additives non-macromolecular inorganic
  • C09D7/62—Additives non-macromolecular inorganic modified by treatment with other compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/60—Additives non-macromolecular
  • C09D7/63—Additives non-macromolecular organic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2300/00—Characterised by the use of unspecified polymers
  • C08J2300/22—Thermoplastic resins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2369/00—Characterised by the use of polycarbonates; Derivatives of polycarbonates
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31507—Of polycarbonate
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31652—Of asbestos
  • Y10T428/31663—As siloxane, silicone or silane

Definitions

• the present invention relates to a coating composition capable of forming a abrasion resistant coating and articles covered with said coating; it specifically relates to a coating composition capable of curing on irradiation with active energy rays and of forming on the surface of a substrate a abrasion resistant coating comprising a cross-linked cured coating which has excellent clarity, abrasion resistance, surface smoothness, heat-resistance, chemical-resistance, durability, weathering resistance, and adhesion to the substrate, and to articles covered with said coating.
• Synthetic resin molded articles such as polymethyl methacrylate resins, polymethacrylimide resins, polycarbonate resins, polystyrene resins, polyolefin resins, and the like, are lighter in weight and superior in impact-resistance compared to glass articles. Because they exhibit a variety of advantages, such as good clarity and ease of molding and processing, they have recently been used in a variety of fields, such as automotive window panes, headlights, tail lights, as well as architectural window panes, highway soundproof barrier walls, and the like.
• Said process provides plastic molded articles with a high degree of abrasion resistance, but these articles are not satisfactorily in durability or weathering resistance, and the coating, which is based on a coating agent comprising a partial hydrolysis condensate of the above silane compound and colloidal silica, exhibits insufficient adhesion.
• a method has been developed to provide a coating with improved adhesion by a prior priming, with an acrylic or silicone or the like, of a plastic molded article for improved adhesion between the molded article and the primer, and then coating the primed layer with the aforementioned coating, thereby providing improved adhesion between said primer layer and the coated layer.
• this coating method involves complicated process steps and does not provide satisfactory properties. Since the coating-curing time is long, the process is economically disadvantageous and also poor in productivity.
• Coating compositions which are essentially free of any non-polymerizable organic solvent, comprising colloidal silica, small amounts of a hydrolysis product of a silylacrylate, photo-polymerization initiators, and polyfunctional acrylates being as main components, have also been disclosed in Japanese Patent Laid-open Publication No. Sho58-1756 (U.S. Pat. Nos.
• compositions generating these abrasion resistant coatings have provided excellent adhesion to substrates with no primer treatment and allowed the coating-curing time to be shortened, but they have tended to make the coating turbid, making it difficult to obtain a completely clear cured coating, and have shown an unsatisfactory balance with durability such as weather resistance, abrasion resistance, and the like.
• the present inventors continued their analysis of the causes for the above problems and discovered that the condensation reaction between the colloidal silica and the radical polymerizable silane compound has been insufficient, causing the resultant chemically modified colloidal silica to exhibit an inferior compatibility with the polyfunctional acrylate, and proposed a photo-polymerizable coating composition as disclosed in Japanese Patent Laid-open Publication No. Hei3-275769, which composition comprised a chemically modified colloidal silica with (meth)acryloyloxy silane upon sufficiently advanced conversion in the condensation reactor, along with bis(acryloyloxyethyl)hydroxyethyl isocyanurate,and a photo-polymerization initiator.
• the cured coatings generated from the above coating composition had good features in that they were free of turbidity and clear, with good optical properties, and with relatively good abrasion resistance under the Taber abrasion test, steel wool test, and the like, as well as with good weather resistance, but none have yet provided an ultraviolet-curable covering material having completely satisfactory properties because of a crack formation problem in a heat cycle test.
• the present inventors discovered that allowing the condensation reaction between the colloidal silica and the (meth)acryloyloxy silane compound to proceed fully has improved, to some extent, the compatibility of the chemically modified colloidal silica with the bis(acryloyloxyethyl)hydroxyethyl isocyanate, but their compatibility has still not been enough, making it impossible to sufficiently suppress the phase separation of these two components in the process of generating a cured coating, which was a major cause of the above deficiency.
• the present invention has been completed on the basis of the discovery that a combined use of a poly(acryloyloxyalkyl)-isocyanurate and a urethane poly(meth)acrylate having an alicyclic skeleton, as the polyfunctional acrylate members, can sufficiently suppress the phase separation of the colloidal silica in the cured coating, not only enabling the formation of a highly heat resistant cured coating with no crack formation in a heat cycle test, but also providing a coating composition capable to generating a coating that can substantially improve the balance with wear resistance and weather resistance.
• the present invention is a coating composition forming a abrasion resistant coating comprising:
• R 1 is an alkylene group with 0-8 carbons
• R 2 and R 3 are alkyl groups with 1-8 carbons
• a is a positive integer of 1-3
• b is a positive integer of 0-2
• a+b is a positive integer of 1-3
• X1, X2, and X3 represent acryloyl, methacryloyl, hydrogen atoms, or alkyl wherein at least two thereof are acryloyloxy or methacryloyloxy groups; R4, R5, and R6 represent an oxyalkylene group or a polyoxyalkylene group), and 10-70 parts by weight of a urethane poly(meth)acrylate (b-2) having an alicyclic skeleton using with at least two (meth)acryloyloxy groups in the molecule (wherein the total amount of components (b-1) and (b-2) is 100 parts by weight); and
• coating compositions capable of generating abrasion resistant coatings of this invention (hereafter abbreviated as coating compositions) are now described below.
• the ultraviolet-curable silicone, component (A) is obtained by chemically modifying particulate colloidal silica, (a-1), with a radical polymerizable silane compound or its hydrolysis product, (a-2), represented by the above General Formula (I).
• the component (a-1), particulate colloidal silica, is a dispersion in water or an organic solvent of super-fine silicic anhydride ultra fine particles having a primary particle size of 1-200 m ⁇ .
• the dispersion media used for the colloidal silica include water; alcoholic solvents such as methanol, ethanol, isopropanol, n-propanol, isobutanol, n-butanol, and the like; polyhydric alcoholic solvents such as ethylene glycol; polyhydric alcohol derivatives such as ethylcellosolve, butylcellosolve, and the like, ketone type solvents such as methylethyl ketone, methylisobutyl ketone, diacetone alcohol, and the like; monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, and the like.
• an alcoholic solvent containing not more than three carbon atoms is preferred in the process of chemical modification reaction with the component (a-2)
• the primary particle size is preferably 1-200 m ⁇ , in particular, 5-80 m ⁇ . Neither a particle size less than 1 m ⁇ , which tends to cause a gelation in the chemical modification step by a component (a-2), nor a cured coating generated from a coating composition containing particulate silica exceeding 200 m ⁇ in primary particle size, which reduces clarity, is preferred.
• Colloidal silica functions to considerably improve the abrasion resistance of the cured coating generated from the coating composition of this invention.
• fine particles such as particulate silica send or the like, exhibits a substantial improvement in the abrasion resistance of the cured coating.
• a dispersion of colloidal silica by itself in an ultraviolet-curable coating composition is substantially poor in dispersibility so that such a coating composition shows an inferior adhesion to the surface of a synthetic resin molded article.
• the present invention has been able to substantially overcome the above difficulty by using a colloidal silica, which has been chemically modified with a component (a-2).
• a colloidal silica which has been chemically modified with a component (a-2).
• the component (a-2), which is a radical polymerizable silane compound represented by the above General Formula (I) or its hydrolysis product, is the component which reacts with the colloidal silica, component (a-1), thereby improving its compatibility with the polyfunctional (meth)acrylate, component (B).
• the component (a-2) used includes a silane compound which shows polymerization activity under ultraviolet irradiation, such as acryloyloxy, methacryloyloxy, or vinyl group; the colloidal silica prepared by chemically modifying with this silane compound, that is, the ultraviolet-curable silicone (A), generates chemical bonds via ultraviolet-induced polymerization with the polyfunctional (meth)acrylate component (B), thereby toughening the resultant cured coating.
• the cured coating prepared by the coating composition of this invention shows a substantially enhanced improvement effect on abrasion resistance to become sufficiently highly resistant to scratching by metal fibers such as steel wool, or the like.
• Component (a-2) includes specifically, for example, at least 1 silane compound selected from 3-methacryloyloxypropyl trimethoxy silane, 3-acryloyloxypropyl trimethoxy silane, 2-methacryloyloxyethyl trimethoxy silane, 2-acryloyloxyethyl trimethoxy silane, 3-methacryloyloxypropyl triethoxy silane, 3-acryloyloxypropyl triethoxy silane, 2-methacryloyloxyethyl triethoxy silane, 2-acryloyloxyethyl triethoxy silane, 3-methacryloyloxypropylmethyl dimethoxy silane, 3-acryloyloxypropylmethyl dimethoxy silane, vinyl trimethoxy silane, vinyl triethoxy silane, and the like, or hydrolysis product thereof.
• silane compound selected from 3-methacryloyloxypropyl trimethoxy silane, 3-acryloyloxyprop
• At least 1 silane compound selected from 3-methacryloyloxypropyl trimethoxy silane, 3-acryloyloxypropyl trimethoxy silane, 3-methacryloyloxypropyl triethoxy silane, 3-acryloyloxypropyl triethoxy silane, vinyl trimethoxy silane, and vinyl triethoxy silane, or its hydrolysis product thereof.
• the hydrolysis products of these silane compounds can be obtained by the usual methods such as stirring at room temperature or with heating 1 mole of a silane compound with or without an organic solvent such as an alcohol solvent, optionally with 0.5-6 moles of a hydrolysis catalyst of 0.001-0.1N hydrochloric acid or an aqueous acetic acid solution or the like.
• an ultraviolet-curable silicone which is a chemically modified colloidal silica using a radical polymerizable silane compound or its hydrolysis product.
• the method of preparing the ultraviolet-curable silicone (A) is the same as that disclosed in Japanese Patent Laid-open Publication No. Hei7-109355 and any detail other than those described here is available as being disclosed in the publication.
• component (A) is carried out in the presence of colloidal silica, a component (a-1), and a radical polymerizable silane compound or its hydrolysis product, component(a-2), by allowing the dispersion medium for the colloidal silica and the lower alcohol generated by the hydrolysis to azeotropically distill off at atmospheric or at reduced pressure, in the presence of a non-polar solvent such as toluene, thereby replacing the dispersion medium with a non-polar solvent, and then heating to carry out a dehydration-condensation reaction step.
• a non-polar solvent such as toluene
• a mixture of a component (a-1) colloidal silica with a component (a-2) radical polymerizable silane compound, along with a hydrolysis catalyst is subjected to the usual methods such as stirring at ambient temperatures or with heating to hydrolyze the silane compound.
• the lower alcohol in the dispersion medium in the colloidal silica and also that generated by the hydrolysis is azeotropically distilled off at atmospheric or at reduced pressure, in the presence of a non-polar solvent, thereby replacing the dispersion medium with the non-polar solvent, followed by treating at a temperature of 60-150° C., preferably at 80-130° C., with the solids concentration being maintained at 30-90% by weight, preferably 50-80% by weight, for 0.5-10 hours with agitation.
• azeotropically distill off the water generated by the condensation reaction along with the non-polar solvent is a good method for increasing the extent of the reaction between components (a-1) and (a-2). It is permissible to use a catalyst such as an acid, a base, a salt, or the like, for the purpose of accelerating the chemical modification reaction.
• the ultraviolet-curable silicone (A) which is a colloidal silica chemically modified by a silane compound prepared in this process, is rendered surface-hydrophobic by coating the surface of the colloidal silica having a hydrophilic surface with a radical polymerizable silane compound or its hydrolysis product, thereby showing an improved compatibility with a monomer mixture (B) comprising a polyfunctional acrylate specified in this invention, so as to give a coating from such a coating composition that has good clarity. Even a particularly thick coating generated in this way is essentially haze-free, which makes this optimum for use in optical articles.
• non-polar solvents used in carrying out the above reactions are selected on the basis of dielectric constants, dipole moments, or hydrogen bond parameters; in a broad sense, it is preferable to use a solvent having a medium degree of polarity for this invention.
• a solvent having a medium degree of polarity for this invention.
• non-polar solvents having a dielectric constant in the range of 2-10 at 20° C. are preferable in this invention.
• Non-polar solvents specifically, for example, include hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cyclohexane, and the like; halogenated hydrocarbons such as trichloroethylene, tetrachloroethylene, and the like, ethers such as 1,4-dioxane, dibutylether, and the like, ketones such as methylisobutyl ketone; esters such as n-butyl acetate, isobutyl acetate, ethyl acetate, ethyl propionate, and the like; polyhydric alcohol derivatives such as ethylene glycol monobutylether and the like.
• hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cyclohexane, and the like
• halogenated hydrocarbons such as trichloroethylene, tetrach
• an unsaturated ethylenic compound such as a monomer having at least one (meth)acryloyloxy group, in the molecule.
• an aromatic hydrocarbon in terms of the reaction between components (a-1) and (a-2); a particularly preferable solvent is toluene.
• the solids concentration during the reaction is preferably in the range of 30-90% by weight.
• a solids concentration less than 30% by weight, with the solvent exceeding 70% by weight, will cause the reaction of the colloidal silica (a-1) with the radical polymerizable silane compound (a-2) to be insufficient so that coating composition containing a colloidal silica chemically modified by a silane compound prepared by such a method will give a cured coating which tends to be poor in clarity.
• the preferred reaction temperature for the components (a-1) with (a-2) is in the range of 60-150° C.
• a reaction temperature less than 60° C. would not allow the reaction to proceed fully, requiring an extended time, while a temperature exceeding 150° C. would cause problems such as reactions other than silanol condensation reactions or gel formation and the like.
• problems would occur such as an opaque reaction system or gel formation and the like; so that the coating composition containing a colloidal silica chemically modified by a silane compound obtained by such a method will give a cured coating which tends to crack.
• An amount of colloidal silica (a-1) less than 40 parts by weight sometimes results in an incomplete reaction, so that a coating composition containing such colloidal silica will give a cured coating with sometimes reduced abrasion resistance or clarity.
• the ultraviolet-curable silicone (A) obtained by chemically modifying colloidal silica (a-1) with a radical polymerizable silane compound (a-2) is a component which improves the abrasion resistance, weather resistance, and durability of the cured coating generated from the coating composition of this invention.
• the use ratio of component (A) in the coating composition should be 1-50 parts by weight, preferably 10-40 parts by weight in solids of a coating composition comprising components (A)-(C).
• a coating composition containing less than 1 part by weight of component (A) will give a coating which fails to show any sufficient improvement in abrasion resistance, weather resistance and durability, while a coating composition with the content of component (A) exceeding 50 parts by weight will give a cured coating which begins to show crack formation.
• component (B) component is one which improves the dispersion stability of the ultraviolet-curable silicone, component (A), in the coating composition of this invention; therefore it is an important component that allows uniform dispersion without any phase separation.
• (B) component mainly comprises components (b-1) and (b-2).
• Poly[(meth)acryloyloxyalkyl] isocyanurate shown by the above General Formula (II), component (b-1), is the component which maintains a high degree of abrasion resistance of the cured coating generated from the coating composition of this invention, and improves the toughness and adhesion of the cured coating.
• Component (b-1) specifically includes, for example, tris(acryloyloxyethyl)isocyanurate, tris(methacryloyloxyethyl)isocyanurate, tris(2-acryloyloxypropyl) isocyanurate, tris(2-methacryloyloxypropyl)isocyanurate, bis(acryloyloxyethyl)hydroxyethyl isocyanurate, bis(methacryloyloxyethyl)hydroxyethyl isocyanurate, bis(2-acryloyloxypropyl)-2-ethoxypropyl isocyanurate, bis(2-methacryloyloxypropyl)-2-hydroxypropyl isocyanurate, tris(acryloyloxyethoxyethyl)isocyanurate, tris(methacryloyloxyethoxyethyl)isocyanurate, bis(acryloyloxyethoxyethyl)-2
• poly[(meth)acryloyloxyalkyl)] isocyanurates, bis(acryloyloxyethyl)hydroxyethyl isocyanurate and tris(acryloyloxyethyl)isocyanurate provide substantial improvements in the toughness, weather resistance, and durability of the cured coating, and thus are preferable.
• Component (b-2) a urethane poly(meth)acrylate with an alicyclic skeleton, along with at least two (meth)acryloyloxy groups in the molecule, is a component which is most effective in improving the dispersion stability of ultraviolet-curable silicone(A) in the coating composition of this invention, thereby preventing the ultraviolet-curable silicone (A) from phase separating in the cured coating generated from the coating material of this invention, so that the coating composition of this invention gives a cured coating with improved toughness, flexibility, crack-resistance, heat-resistance, and weather resistance, as well as the clarity of the cured coating.
• the urethane poly(meth)acrylate used in this invention is highly compatible with the ultraviolet-curable silicone (A) so as to enable the provision of a clear cured coating, even when a thick coating is formed.
• the urethane poly(meth)acrylate (b-2) having an alicyclic skeleton includes a urethane formation reaction product between a (meth)acrylate containing a hydroxyl group and a polyisocyanate compound having an alicyclic skeleton and two or more isocyanate groups in the molecule, and a urethane reaction product obtained by synthesizing adducts by treating a polyisocyanate having an alicyclic skeleton and two or more isocyanate groups in the molecule with a polyol, polyether, polyester or polyamide diol, followed by adding a hydroxyl-containing (meth)acrylate to the remaining terminal isocyanate group.
• Polyisocyanate compounds having alicyclic skeletons are specifically, for example polyisocyanate monomers, such as isophorone diisocyanate, 4,4′-methylenebis(cyclohexyl)isocyanate, methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and like the biuret trimers thereof, and adducts of these compounds with various polyols and the like.
• polyisocyanate monomers such as isophorone diisocyanate, 4,4′-methylenebis(cyclohexyl)isocyanate, methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and like the biuret trimers thereof,
• polyols which are used for the synthesis of the adducts are specifically, for example, alkylpolyols such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, trimethylol propane, pentaerythtol, sorbitol, mannitol, glycerin, and the like, and polyether polyols derived therefrom; polyester polyols synthesized from polyhydric alcohols and polybasic acids, polyester polyols such as polycaprolactone polyols and the like.
• alkylpolyols such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, trimethylol propane, pentaerythtol, sorbitol, mannitol, glycerin, and the like, and polyether polyols derived therefrom
• the (meth)acrylates containing hydroxyl groups include, specifically, hydroxyalkyl(meth)acrylates such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, and the like; addition reaction products of monoepoxy compounds such as butyl glycidyl ether, 2-ethylhexylglycidyl ether, glycidyl methacrylate and the like, with acrylic acid or methacrylic acid; monoacrylate esters or monomethacrylate esters with polyethylene glycol, polypropylene glycol; monoacrylate esters or methacrylate esters of polycaprolactone diol, and the like.
• hydroxyalkyl(meth)acrylates such as 2-hydroxyethyl acrylate, 2-
• a hydroxyalkyl(meth)acrylate containing not more than 4 carbon atoms in this invention is preferred because it is more compatible with component (A), particularly 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, and 4-hydroxybutyl acrylate are preferable.
• the reaction of the polyisocyanate with a diol and a (meth)acrylate containing a hydroxyl group is carried out in the presence of a tin-type catalyst such as n-butyl tin dilaurate, or the like, with about equivalent amounts of the isocyanate and hydroxyl groups, by heating several hours at 60-70° C.
• a tin-type catalyst such as n-butyl tin dilaurate, or the like
• the reaction product which is in general often highly viscous, is preferably diluted with an organic solvent or other diluting monomer during or after the end of the reaction.
• the component (b-2) in this invention uses a urethane poly(meth)acrylate obtained by treating the above polyisocyanate compound with a hydroxy-containing (meth)acrylate, but in terms of compatibility with component (A), it is preferred to use a urethane poly(meth)acrylate represented by the General Formula (III) below. From among these, it is preferred to use a urethane poly(meth) acrylate obtained by treating one mole of isophorone diisocyanate with 2-2.5 moles of a hydroxyalkyl (meth)acrylate because it gives a cured coating with excellent heat resistance and weather resistance.
• a urethane poly(meth)acrylate obtained by treating one mole of isophorone diisocyanate with 2-2.5 moles of a hydroxyalkyl (meth)acrylate because it gives a cured coating with excellent heat resistance and weather resistance.
• a molar ratio less than 2 will result in the polyisocyanate component remaining unreacted, where the residual isocyanate will later react with water to generate urea so that such a cured coating will undergo a change with time, resulting in the unfavorable phenomenon of a yellowing coating or the like.
• a ratio exceeding 2.5 will cause the hydroxyl-containing (meth)acrylate to remain in excess so that the cured coating will become hydrophilic, reducing its water resistance or weather resistance.
• R 7 and R 8 represent alkyleneoxy or polyalkyleneoxy group.
• urethane poly(meth)acrylates may be used singly or as a mixture of two or more.
• a monomer disclosed in Japanese Patent Laid-open Publication No. Hei7-109355 it is preferred to make a combined use of an alkylene glycol di(meth)acrylate (b-3), represented by General Formula (V) given below.
• R 12 represents a branch or linear hydrocarbon group with 4-12 carbons
• X 9 and X 10 are acryloyl to methacryloyl group.
• specific examples suitable for providing a cured coating with substantial improvement in adhesion include 1,6-hexane diol diacrylate and 1,9-nonane diol diacrylate.
• component (b-3) may be within the range of not more than 20 parts by weight per 100 parts by weight of component (B), preferably in the range of 2-20 parts by weight, more particularly in the range of 5-15 parts by weight.
• this component (b-3) exceeds 20 parts by weight, this will give a cured coating with reduced abrasion resistance or curability, in addition, it will show reduced compatibility with the ultraviolet-curable silicone (A), thereby resulting in a cured coating with reduced clarity.
• the use ratio of component (B) should be 45-95 parts by weight, preferably 60-90 parts by weight per 100 parts by weight of the coating composition comprising components (A)-(C).
• a use ratio of (B) less than 45 parts by weight fails to give sufficient toughness, adhesion, heat resistance, or weathering resistance, while a level exceeding 95 parts by weight will reduce abrasion resistance.
• the coating composition of this invention contain a photo-polymerization initiator (C).
• Component (C) specifically includes, for example, carbonyl compounds such as benzoin, benzoin methylether, benzoin ethylether, benzoin isopropylether, benzoin isobutylether, acetoin, butyroin, toluoin, benzil, benzophenone, p-methoxybenzophenone, diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, methylphenyl glyoxylate, ethylphenyl glyoxylate, 4,4-bis(dimethylaminobenzophenone), 2-hydroxy-2-methyl-1-phenylpropane-1-on, 1-hydroxycyclohexylphenyl ketone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-on, and the like; sulfur compounds such as tetramethylthiuram disulfide, and the like; azo compounds such as azobisisobuty
• Preferred initiators are, for example, benzophenone, methylphenyl glyoxylate, 2-hydroxy-2-methyl-1-phenylpropane-1-on, 1-hydroxycyclohexylphenyl ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; and these may be used alone or in combination of two or more.
• the use ratio of components (C) should be 0.01-5 parts by weight, preferably 0.1-3 parts by weight, per 100 parts by weight of a coating composition comprising components (A)-(C).
• a use ratio of component (C) exceeding 5 parts by weight causes coloration of the cured coating, lowering its weathering resistance.
• a level less than 0.01 parts by weight causes the polymerization reaction to be incomplete.
• components (A)-(C) are essential components that constitute the coating composition of this invention, but one may add to the coating composition of this invention with the objectives of improving weather resistance and durability an ultraviolet absorber as component (D) and a photo-stabilizer as component (E).
• Component (D) ultraviolet stabilizer is not particularly limited and any type can be used if it is uniformly soluble in the composition and provides good weather resistance; but in terms of good solubility and improved weather resistance with respect to the composition, it is preferred to use an ultraviolet absorber which is a compound derived from benzophenone, benzotriazole, phenylsalicylate, phenyl benzoate types having a wavelength of maximum absorption being in the range of 240-380 nm.
• a benzophenone type ultraviolet absorber is preferred in that it can be incorporated in large amounts in the composition and a benzotriazole ultraviolet absorber is preferred from the standpoint of preventing a substrate such as polycarbonate from yellowing.
• Ultraviolet absorbers include specifically, for example,
• the amount of the ultraviolet absorber used is preferably in the range of 3-10 parts by weight per 100 parts by weight of a coating composition comprising components (A)-(C) and a level less than 3 parts by weight does not give sufficient effect of addition while a level exceeding 10 parts by weight begins to cause the cured coating to have lowered abrasion resistance.
• Such photo-stabilizers when used in combination with an ultraviolet absorber, further improves the weather resistance of the cured coating.
• the hindered amine photo-stabilizers specifically include, for example, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, 2-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-n-butylmalonic acid bis(1,2,2,6,6-pentamethyl-4-piperidyl), and the like.
• bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate is particularly preferred.
• the amount of the photo-stabilizer used is preferably in the range of 0.05-1 part by weight per 100 parts by weight of a coating composition comprising components (A)-(C).
• the coating composition of this invention may further optionally contain additives such as an organic solvent, an antioxidant, a yellowing inhibitor, a bluing agent, a pigment, a leveling agent, a defoamer, a viscosity enhancing agent, a sedimentation inhibitor, an anti-static agent, an anti-hazing agent, and the like.
• additives such as an organic solvent, an antioxidant, a yellowing inhibitor, a bluing agent, a pigment, a leveling agent, a defoamer, a viscosity enhancing agent, a sedimentation inhibitor, an anti-static agent, an anti-hazing agent, and the like.
• the organic solvent used as a component (F) organic solvents can provide the coating composition of this invention with improved uniform solubility, dispersion stability, adhesion to substrate, flatness and uniformity of the coating, and the like, and can be used in amounts of 100-500 parts by weight, preferably in the range of 150-300 parts by weight per 100 parts by weight of the total amount of components (A)-(E).
• the organic solvent (F) is not particularly limited in types, but specifically includes at least one type selected from organic solvents such as alcohols, hydrocarbons, halogenated hydrocarbons, ethers, ketones, esters, polyhydric alcohol derivatives, and the like.
• organic solvents such as alcohols, hydrocarbons, halogenated hydrocarbons, ethers, ketones, esters, polyhydric alcohol derivatives, and the like.
• a mixture of organic solvents comprising combination of at least 1 type selected from isobutanol and n-butanol, as a component (f-1), at least 1 type selected from n-butyl acetate, and isobutyl acetate as a component (f-2), and at least 1 type selected from 3-methoxy-1-propanol, 3-methoxy-2-propanol, 3-methoxy-1-butanol and 3-methoxy-2-butanol, as component (f-3).
• the amount of the coating composition applied is preferably in such range as to provide the coated thickness of the cured coating in the range of 3-30 ⁇ m, preferably 5-25 ⁇ m, most preferably, 8-20 ⁇ m.
• a coating thickness in less than 3 ⁇ m fails to give sufficient abrasion resistance, while a level exceeding 30 ⁇ m may decrease the adhesion to the substrate or tend to cause crack formation of the coating.
• the means used for curing the applied coating on the substrate include the method known in the art of irradiating with actinic energy rays such as ⁇ , ⁇ and ⁇ rays, but it is preferred to use ultra-violet as a means to cure the coating composition of this invention.
• the source for generating ultraviolet light in terms of practicality and economics, an ultraviolet lamp is generally used. Specifically, included are a low pressure mercury lamp, a high pressure mercury lamp, a super high pressure mercury lamp, a xenon lamp, a metal halide lamp, and the like.
• the atmosphere for the irradiation may be air or may be an inert gas such as nitrogen, argon, and the like.
• the coating composition of this invention After the coating composition of this invention has been applied to the surface of a synthetic resin molded article, but before it is cured by an ultraviolet radiation energy, one may carry out a heat treatment using infrared light or a hot air oven at 20-120° C. for 1-60 minutes, with the objective of improving the adhesion of the cured coating to the substrate.
• the coating composition of this invention can be used to improve the surface of a variety of synthetic resin molded article substrates.
• the synthetic resin molded articles include a variety of thermoplastic resins and thermosetting resins, for which it has been desired to improve abrasion resistance, weather resistance, and the like.
• thermoplastic resins and thermosetting resins for which it has been desired to improve abrasion resistance, weather resistance, and the like.
• polymethylmethacrylic resins polycarbonate resins, polyester resins, polystyrene resins, polyolefin resins, acryonitrile-styrene copolymer resins, polyamide resins, polyarylate resins, polymethacryamide resins, polyallyldiglycol carbonate resins, and the like.
• substrates such as polymethylmethacrylic resin, polycarbonate resin, polystyrene resin, polymethacrylamide resin because they are excellent in clarity and are in strong need for improvement of abrasion resistance.
• Synthetic resin molded articles include resin sheet molded articles, film molded articles, various injection molded articles, and so on.
• An abrasion test was carried out under conditions of an abrasive wheel CS-10F, load 500 g, number of revolutions at 500 cycles, according to ASTM D-1044. After the abrasion test, the sample was washed using a neutral detergent and its haze value was measured using a haze meter. Abrasion resistance is shown by the value of (the haze value after abrasion ⁇ haze value before abrasion).
• a piece of #000 steel wool (manufactured by Nippon Steel Wool Co., Ltd, “Bonstar” [phonetically translated] trademark) was attached to a 1 cm 2 circular pad; this pad was placed on the surface of a sample held on a reciprocating abrasion tester table and the sample was subjected to abrasion test at 50 cycles under a load of 1000 g. The sample was washed with a neutral detergent and its haze value was measured by a haze meter. Abrasion resistance is expressed by (the haze value after abrasion ⁇ haze value before abrasion).
• the surface of a sample was cut to reach into the substrate making 11 longitudinal and transverse lines at a 1.5 mm gap between each line amounting to 100 grids; a piece of cellophane tape (25 mm wide, manufactured by Nichiban Co., Ltd.) was pressed against the grids and is then removed upward abruptly.
• the evaluation of the adhesion is expressed in terms of the number of remaining grids/the number of total grids (100).
• the haze value according to ASTM D-1003 was measured using a haze meter.
• Clarity was evaluated in a dark place by illuminating the sample surface with a halogen lamp being as a light source (Device: ESCA ILLUMINATOR, MODELELI-050, manufactured by Mitsubishi Rayon Co. Ltd.) to be designated according to the following standard:
• a sample was held for 200 hours in a 130° C. hot air oven and it was visually inspected to evaluate heat resistance.
• IPA-ST IPA-ST
• TSL-8370 3-methacryloyloxy propyltrimethoxy silane
• TSL-8370 3-methacryloyloxy propyltrimethoxy silane
• the volatile components such as alcohol, water, and the like, were allowed to distill off under atmospheric conditions, followed by adding 600 parts of toluene when the concentration of solids (the total amount of the 600 parts of IP-ST SiO2 and 317 parts of TSL-8370 amounting to 917 parts), reached about 60% and azeotropically distilling off alcohol and water, along with toluene.
• the solids concentration was about 40% by weight.
• the reaction was further carried out at for 4 hours at 110° C., while toluene was allowed to distill off to bring the solids concentration to about 60% by weight.
• the resultant ultraviolet-curable silicone (hereafter abbreviated as SC-1) was a yellowish Newtonian-fluid-type clear and viscous liquid and had a viscosity of 20 centipoise at 25° C.
• the solids concentration was 61% by weight in terms of residue on heating. The residue on heating is expressed by (weight in g after heating/weight before heating in g) ⁇ 100% by weight under heating conditions of 3 hours at 105° C.
• a ultraviolet-curable silicone (SC-2) was synthesized by an operation similar to that for Synthetic Example 1, except for changing the amounts of IP-ST to 2290 parts and TSL-8370 to 295 parts.
• the resultant ultraviolet-curable silicone (SC-2) was a yellow Newtonian-fluid-type clear and viscous liquid and had viscosity of 14 centipoiseat 25° C.
• the solids concentration was 61% in terms of residue on heating.
• a ultraviolet-curable silicone (SC-3) was synthesized by an operation similar to that for Synthetic Example 1, except for changing the amounts of IP-ST to 1,637 parts and TSL-8370 to 491 parts.
• the resultant ultraviolet-curable silicone (SC-3) was a yellow Newtonian-fluid-type clear and viscous liquid and had a viscosity of 42 centipoiseat 25° C.
• the solids concentration was 61% in terms of residue on heating.
• a 2-liter 3-necked flask provided with a stirrer and thermometer were metered in 365.4 parts of 2-hydroxyethyl acrylate, 0.45 parts of di-n-butyltin dilaurate, and 0.4 parts of hydroquinone monomethylether, followed by stirring at 55° C. and adding dropwise in 3 hours, 543.1 parts of a triisocyanate (tradename: Duranate TPA-100, manufactured by Asahi Kasei Kogyo Co., Ltd.), a trimer of hexamethylene diisocyanate and having an isocyanurate skeleton. After the end of the dropwise addition, the reaction was further continued for 8 hours at 70° C. when the viscosity increased so that n-butyl acetate was used to dilute to give a urethane triacrylate (UPA-3) having a final solids concentration of 90% by weight.
• UPA-3 urethane triacrylate
• a coating composition was prepared according to the composition given in Table 1. This coating composition was spray coated to a thickness of 3 mm on a methacrylic resin injection molding sheet (Acrypet VH, color tone 001, clear, manufactured by Mitsubishi Rayon Co., Ltd.), followed by being left to dry for 5 minutes at room temperature and then heat-dried for 5 minutes at 80° C. in a drier. Then, the dried sample in an air environment was irradiated with ultraviolet light at 1,000 mJ/cm 2 (ultraviolet integrated energy at wavelength 320-380 nm) using a high pressure mercury lamp to obtain a abrasion resistant methacrylic resin sheet with a 10 ⁇ m cured coating film thickness. Table 2 shows the results of performance evaluation.
• Coating compositions with the compositions given in Table 1 were prepared.
• the coating compositions were spray coated to a thickness of 3 mm onto polycarbonate resin injection molded sheets (Lexan LS-2, color tone 111, clear, manufactured by General Electric Company), followed by being left to dry for 5 minutes at room temperature, and heat-dried for 5 minutes at 80° C. in a drier. Then the dried sample was irradiated in an air environment with ultraviolet light at 2,000 mJ/cm 2 (ultraviolet integrated energy at wavelength 320-380 nm) using a high pressure mercury light to give abrasion resistant polycarbonate resin sheets with a 10 ⁇ m cured coating film thickness.
• the results of performance evaluation are given in Table 2.
• Example 2 was repeated, except for replacing the UPA-1 of example 2 with 24 g of UPA-4, to give a abrasion resistant resin sheet with a 10 ⁇ m cured coating film thickness.
• the results of performance evaluation are given in Table 2.
• UPA-1 A urethane di(meth)acrylate having an alicyclic skeleton
• UPA-2 A urethane di(meth)acrylate having an alicyclic skeleton
• UPA-3 A nonaromatic, cyclic aliphatic urethane poly(meth)acrylate
• UPA-4 A linear chain aliphatic urethane poly(meth)acrylate
• TAEIC Tris(acryloyloxyethyl)isocyanurate (tradename: ARONIX M-315, manufactured by Toa Gosei Chemical Industries Co., Ltd)
• BAEIC Bis(acryloyloxyethyl)hydroxyethyl isocyanurate (tradename: ARONIX M-215, manufactured by Toa Gosei Chemical Industries Co., Ltd))
• NDDA 1,9-Nonane diacrylate (tradename: VISKOT #260, manufactured by Osaka Organic Chemical Industries, Co., Ltd.)
• APO 2,4,6-trimethylbenzoyldiphenylphosphine oxide (tradename: LUCERIN-TPO, manufactured by BASF)
• MPG Methylphenyl glyoxylate (tradename: BAICURE 55, manufactured by Stauffer)
• UVA 2-(hydroxy-5-tert-butylphenyl)benzotriazole (tradename: TINUVIN-PS, manufactured by Ciba Geigy Co., Ltd.)
• HALS bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate (tradename: SANOL LS-770, manufactured by Sankyo Co., Ltd.)
• Example 2-13 and Comparative Examples 1-8 received 5 parts by weight of UVA and 0.2 parts by weight of HALS per 100 parts by weight of the coating compositions of Table 1.
• Comparative Example 4 is a comparative example corresponding to an example of Japanese Patent Laid-open Publication No. Hei3-275769; Comparative Example 9 is an example using an aliphatic urethane poly(meth)acrylate, corresponding to an example of Japanese Patent Laid-open Publication No. Hei4-214743.
• the coating composition of this invention is excellent not only in curability but also in the effect of improving abrasion resistance of synthetic resin molded articles, and is particularly useful in automotive related parts that strongly demand durability and weather resistance, particularly for applications in headlight lenses, tail lights, side lights and the like.

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• 1996
  • 1996-09-20 WO PCT/JP1996/002723 patent/WO1997011129A1/ja active IP Right Grant
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  • 1996-09-20 KR KR10-1998-0702041A patent/KR100440702B1/ko not_active IP Right Cessation
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